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Radiographic Anatomy Flashcards Preview

Properties of an X-ray

-travel straight lines at the speed of light-diverge in space from the source-cause certain crystals to flourecence-cannot be detected by the human eye-differential absorbtion-cannot be refracted by lens-produce biological effects

Producing a radiograph

Image formation

-x ray tube, source of electrons-xray beam, focused source of photons based on density-object, beam absorbed or passed based on density-film, photons pass object to strike film with silver coatingImage - record of proton interactions

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Xray Photons

produced when electrons hit the target

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Xray photon interactions

xray photons penetrate object, absorbed or pass thru to hit film

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Xray beam

-is cone shaped from a point source-the most central portion is called central ray-the central ray diverges less and gives the truest image-typically the beam will be perpendicular to the film

X ray photon Pass thru

Xray photons absorbed

Image Terminology

ProjectionBody Position

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Projection

Anteroposterior/Posteroanterior - x ray beam enters AP front to back or PA back to frontLateral - x ray beam enters side project side of patient alone coronal plane and travels left to right, names for which side is against the filmOblique - positioned on film so X-ray passes thru at 45 degree angle

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Body Position

Upright - AP or PA or lateralRecumbent - supine or prone or lateralOblique - right or left and anterior or posteriorDecubitis - laying on side and take PA or AP

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Upright Positions

patient standsallows for veal to postural informationchiros can use this to analyze upright lumbar and sacral

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Recumbent

patient laying downno reliable evaluation of postural elementsuseful when patient is in a lot of pain

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Minimum Diagnostic Series

-standard views required to evaluate an area-variation by facility or circumstance-add more views depending on case-must take at least 2 views-projection oriented 90 degrees to one another-view 3D object in 2D

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Choice of Postioning

place the structures closest to the filmstarts with standard serieswhat structures you wish to visualizepatients clinical presentationdifferent diagnosis under considerationpatients sizepatients protection (female pelvis)

Radiographic evaluation

have a systmuse the system every timebe thorough

Extent of Evaluation

you are legally responsibleevaluate the whole xrayevaluate for all pathologies/conditions

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Method of Evaluation

A - alignmentB - BoneC - CartilageS - soft tissue

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Search PatternSteps in Evaluation

know the ABCS for each regionsteps: - identify the study-identify the informational markers- note collimation, shielding and artifacts-the the technical quatlity of the film- evaluate anatomy using ABCS search pattern

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Normal Anatomy

the first step om recognizing abnormalities on radiographs is to know the appearanfce of notmal radiographic anatomy-each person is a unique anatomical entity-anatomical variations exist that are normal or abnormal-pathology ften alters anatomical structures-may be present with no radiographically visible alterations in anatomical structures

Atlantodental Interspace (Interval)

McGregor's Line

Posterior-superior margin of hard palate to inferior most surface of the occiputtip of dens to the line: <10mm in females

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Relevant soft tissues of the Lateral Cervical

pharyngeal air shadowlaryngeal air shadowtracheal air shadownote calcification of cartilagesposterior cervical soft tissues

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AP lower cervical

used to visualize the structures of C3-C7 vertebral bodies-good to also see the postior elements but they come in variavle in sizesee the articular pillars and SP's and other oblique structures

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AP Open Mouth

used to visualize the structures of C0-C1 articulation and the C1-C2 joint space-you also see the lateral masses of C1 and the arches-odontoid process, paraodontoid notches, body of C2, skull, madible, and dental structures

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Georges Line

Lateral spine (neutral, flexed, or extended)a line is drawn along the posterior aspect of the vertebral bodies to extrapolate across disc space-offset indicates anter or retrolithesis having a translation of >= 4mm as the indicator

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Sagittal Dimention of Cervical Spine Canal

lateral cervicalposterior surface of mid vertebral body to spinolaminar junction-there are minimum measurements for this one at each vertebral bodyC1-16mm, C2-14mm, C3-13mm, C4-7-12mmpositive shows the patient may have canal stenosis

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Atlantoaxial Alignment

seen on the AP open mouthlateral mass of atlas should not overhang lateral margin of C2 superior facet (>1mm)>=2mm overhang shows the patient may be suspect to a Jefferson's fracturethis may be normal in children 4 years of age or youngeryou can draw an X from one C0-C1 joint to the opposite C1-C2 joint and the and by doing the same on the other side you can determine rotation at the C1-C2 joint

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Coronal Dimensions of the Cervical Spine

measure the shortest distance between the inner cortical margins of pedicles at given segment, cary by spinal level, evaluated for stenosis

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Cervical Gravity Line

Lateral neutral cervicalvertical line drawn through the apex of odontoid process should pass through the seventh cervical vertebral bodygross assessment of where the gravitational stresses are acting at the C/T junctionRuth Jackson stress lines on flex/extension can also assess stress focus

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Angle of Cervical Curve

lateral cervical two lines are drawn, one through and parallel to the inferior endplate of the 7th cervical body and the other through the midpoints of the anterior and posterior tubercles of the atlasconstruct perpindiculars and measure the angle, normally 35 - 45 degreeslack of lordosis may indicate trauma, muscle spasm, or degenerate diseasemany stress lack of correlation between curve and symptoms

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Prevertebral soft tissue

lateral cervicalspace measured between the vertebral bodies and the air shadow of the pharynx, larynx and tracheanormally 10mm at C1rules of 2's and 6'sC2 < 6mmC6 < 22mmincreases with any soft tissue mass (hematoma, abscess or tumour)